import numpy as np

a1 = np.array([1, 2, 3, 4])

a2 = np.array([
    [1, 2, 3],
    [4, 5, 6],
    [7, 8, 9]
])
print(a2[2])
print(a2[2,1])
print(a2[:2])
a3 = np.array([
    [[10, 11, 12], [13, 14, 15], [16, 17, 18]],
    [[20, 21, 22], [23, 24, 25], [26, 27, 28]],
    [[30, 31, 32], [33, 34, 35], [36, 37, 38]]
])
print(a3.shape)
print(a3[1])
print(a3[2,0])
print(a3[0,2,1])

